1. Field of the Invention
This invention relates to power management circuits and, more particularly, to a current limiting protection circuit.
2. Description of the Related Art
Power management devices, such as voltage regulators, typically include circuitry to limit the output current and short circuit current. A common technique to achieve current limitation is to create a feedback loop that senses the output current of the regulator and lowers the output voltage so that output current is held constant when a certain level of current is reached. In this technique, the current control loop has to operate at the same time as the voltage control loop and is usually difficult to keep stable. Also, it is difficult to make such a second control loop very fast. This solution limits the current to a fixed value and is usually not very accurate.
Another technique to limit the output current of the voltage regulator is to pull the reference to the regulator to ground. However, this technique may require two feedback loops and as such is usually difficult to keep stable.